Application: systemsettings5 (5.3.1)

Qt Version: 5.4.1
Operating System: Linux 3.19.8-031908-generic x86_64
Distribution: Ubuntu 15.04

-- Information about the crash:
Opened System Settings and then clicked on Workspace THeme. I don't know what's going on but every time I do that  Application Settings crash in this session.

This is the first time I'm experiencing the issue. Until now it was always working. I don't know what has changed...
However until now I haven't exp

The crash can be reproduced sometimes.

-- Backtrace:
Application: System Settings (systemsettings5), signal: Aborted
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f68fd36b780 (LWP 9178))]

Thread 3 (Thread 0x7f68eadaa700 (LWP 9179)):
#0  0x00007f68f9ad68dd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f68f7df0b72 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007f68f7df264f in xcb_wait_for_event () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007f68edb65099 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#4  0x00007f68fa157b0e in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f68f6d0a6aa in start_thread (arg=0x7f68eadaa700) at pthread_create.c:333
#6  0x00007f68f9ae1eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7f68dbc45700 (LWP 9180)):
#0  0x00007f68f9ad68dd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f68f67ebebc in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f68f67ebfcc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f68fa3eec6c in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f68fa3933e2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f68fa152b44 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f68f911df65 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#7  0x00007f68fa157b0e in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f68f6d0a6aa in start_thread (arg=0x7f68dbc45700) at pthread_create.c:333
#9  0x00007f68f9ae1eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f68fd36b780 (LWP 9178)):
[KCrash Handler]
#6  0x00007f68f9a10267 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:55
#7  0x00007f68f9a11eca in __GI_abort () at abort.c:89
#8  0x00007f68fa144edf in QMessageLogger::fatal(char const*, ...) const () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007f68f8bc5791 in QSGRenderLoop::handleContextCreationFailure(QQuickWindow*, bool) () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#10 0x00007f68f8bcf06f in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#11 0x00007f68f8bcf30a in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#12 0x00007f68fabcd7b5 in QWindow::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#13 0x00007f68f8c00dd3 in QQuickWindow::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#14 0x00007f68fb181b2c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#15 0x00007f68fb187000 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#16 0x00007f68fa395c2b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#17 0x00007f68fabc5e86 in QGuiApplicationPrivate::processExposeEvent(QWindowSystemInterfacePrivate::ExposeEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#18 0x00007f68fabc6bbd in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#19 0x00007f68fabab34f in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#20 0x00007f68edb8f590 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#21 0x00007f68f67ebc3d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#22 0x00007f68f67ebf20 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#23 0x00007f68f67ebfcc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#24 0x00007f68fa3eec57 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#25 0x00007f68fa3933e2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#26 0x00007f68fa39b02c in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#27 0x000000000040ef6b in main ()

Reported using DrKonqi